<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./lib/vue.min.js"></script>
</head>
<body>
    <div id="app">
        <input type="text" v-model = "n1">

        <select v-model = "opt">
            <option value="+">+</option>
            <option value="-">-</option>
            <option value="*">*</option>
            <option value="/">/</option>
        </select>

        <input type="text" v-model = "n2">
        <input type="button" value="=" @click = "calc">
        <input type="text" v-model = "result" >
    </div>
    
    <script>
        var vm = new Vue({
            el:"#app",
            data:{
                n1:'',
                n2:'',
                result:'',
                opt:'+'
            },
            methods: {
                calc() { //计算机计算方法
                  //逻辑
                    // switch(this.opt){ 
                    //     case "+":
                    //         this.result = parseInt(this.n1) + parseInt(this.n2)
                    //         break;
                    //     case "-":
                    //         this.result = parseInt(this.n1) - parseInt(this.n2)
                    //         break;
                    //       case "*":
                    //         this.result = parseInt(this.n1) * parseInt(this.n2)
                    //         break;
                    //       case "/":
                    //         this.result = parseInt(this.n1) / parseInt(this.n2)
                    //         break;
                    // }
                    
                    //注意这是投机取巧的方式，正式开发中尽量少用
                    var codeStr = 'parseInt(this.n1)' + this.opt + 'parseInt(this.n2)'
                    this.result = eval(codeStr) 
                }
            }
        })
    </script>
</body>
</html>